Key Event Handling in java:
Key events in java are generated when a key is pressed, the key is typed and a key is released. The key Listener interface is handling key events.Each of the key event handling methods takes a keyEvent object is its arguments.
A key event object contains information about the key event. The various methods available in the keyListener interface are as follows:
void keyPressed(keyEvent e)
The keyPressed ()method is used to call when a key is pressed.void keyTyped(keyEvent e)
The keyTyped ()method is used to call when a key is typed.void KeyReleased(keyEvent e)
The keyReleased()method is used to call when typed or continuously pressed a key is released.getKeyChat()
The getKeyChat()method is used to return the character of the key from which the event is generated.Sample Program for key event handling in java:
import java.awt.*;import java.awt.event.*;
import java.applet.*;
/*<applet code="impkey" width=200 height=300></applet>*/
public class impkey extends Applet implements KeyListener
{
TextField t
TextArea ta;
pulic void init()
{
t=new TextField(20);
ta=new TextArea();
add(t);
add(ta);
t.addKeyListener(this);
}
public void keyPressed(KeyEvent ke)
{
if(ke.getSource()==t)
ta.append("key pressed");
}
public void keyPressed(KeyEvent ke)
{
if(ke.getSource()==t)
ta.append("keyPressed");
}
public void keyReleased(keyEvent ke)
{
if(ke.getSource()==t)
ta.append("Key Released");
}
public void keyTyped(KeyEvent ke)
{
if(ke.getSource()==t)
{
char c=ke.getKeyChar();
ta.append("KeyTyped"+c);
}
}